Two-Dimensional Janus FeXY (X, Y = Cl, Br, and I, X ≠ Y) Monolayers: Half-Metallic Ferromagnets with Tunable Magnetic Properties under Strain

Abstract

Two-dimensional (2D) ferromagnetic materials with high spin polarization are highly desirable for spintronic devices. 2D Janus materials exhibit novel properties due to their broken symmetry. However, the electronic structure and magnetic properties of 2D Janus magnetic materials with high spin polarization are still unclear. Inspired by the successful synthesis of a ferromagnetic FeCl2 monolayer and 2D Janus MoSSe and WSSe, we systematically study the electronic structure and magnetic properties of Janus FeXY (X, Y = Cl, Br, and I, X ≠ Y) monolayers. Based on the Goodenough–Kanamori–Anderson theory, the ferromagnetism stems from the superexchange interaction mediated by Fe–X/Y–Fe bonds. The band gaps of spin-up channels are large enough (>4 eV) to prevent spin flipping, which is beneficial for spintronic devices. Additionally, the sizable magnetocrystalline anisotropy energy (MAE) indicates that Janus FeXY monolayers are suitable for information storage. More importantly, the half-metallic character is still kept in Janus FeXY monolayers, and their magnetic properties are enhanced by the biaxial compressive strain. The MAE of FeClI and FeBrI increases by 1 order of magnitude, and the Curie temperature of FeXY monolayers enhances by 100%. These results provide an example of the 2D Janus half-metallic materials and enrich the 2D magnetic material library.

First-principles calculations of the BeO monolayer with chemical functionalization

“…Herein there are small imaginary frequencies at G points for half-hydrogenation and half-fluorination (À0.18 and À0.06 THz), which occur in many 2D materials. 34 This can be solved using a larger supercell, 34 indicating the dynamic stability. Moreover, the framework of the BeO supercell after half-fluorination is well preserved during the AIMD period as shown in Fig.…”

A review on emerging developments in thermal and moisture management by membrane‐based clothing systems towards personal comfort

“…One of the proposed strategies to develop thermal management structures is using thermally conductive fillers such as boron nitride (BN) 212,213 . Using a well interpenetrated BN network within a nanofibrous membrane, highly thermal conductive breathable NFMs can be developed 7 . In‐plane and out‐plane thermal conductivity was 17.9 and 0.29 W m −1 K −1 , in the composite membrane obtained in this method.…”

“…Focusing on ventilation of the microclimate between skin and next to skin clothing instead of the whole indoor space ventilation is one of the main trajectories to reduce the greenhouse gas emission, carbon footprint and global warming 1–6 . This concept has also driven researchers to devote continuous efforts to improve the performance of outdoor clothing towards enhanced smart heat and moisture management functionalities 7,8 …”

Tunable topology and berry curvature dipole in transition metal dichalcogenide Janus monolayers

“…After the synthesis of MoSSe, other two-dimensional Janus structures were also predicted to exist. The halfmetallic, ferromagnetic FeXY [18], TMDC oxides WXO [19], In 2 SSe, the Janus analogue of binary compounds InSe and InS [20] and Janus structures derived from metal monochalcogenides [21] are a few examples. The different Janus materials show several intriguing properties [22][23][24], including the aforementioned large Rashba effect [25], tunable Dzyaloshinskii-Moriya interactions [26], piezoelectricity and novel valleytronic effects [27][28][29][30].…”